Android Error On Tutorial Cannot Find Symbol Variable Activity_display_message

I am trying to learn android app building through tutorials and Android Studio. Some of the comments regarding xml and imports were helpfult. I am down to one error. I get this err

Solution 1:

I had this same problem. Under the "Build an Intent" section in the Android Studio instructions, it's easy to miss this line:

publicfinalstaticStringEXTRA_MESSAGE="com.example.myfirstapp.MESSAGE";

Make sure this is included above the @Override in MainActivity.java and you're all set :)

Solution 2:

Don't know if anyone still need the answer to this, but I figured it out like this:

I saw this in the tutorial:

Note: The XML layout generated by previous versions of Android Studio might not include the android:id attribute. The call findViewById() will fail if the layout does not have the android:id attribute. If this is the case, open activity_display_message.xml and add the attribute android:id="@+id/activity_display_message" to the layout element.

So, under Res -> layout -> activity_display_message.xml, I entered the line

android:id="@+id/activity_display_message"

Anywhere inside the RelativeLayout tags. In my case specifically, I randomly shoved it in-between the android:paddingTop and tools:context fields

Hope this helps :D

Solution 3:

I think:

ViewGrouplayout= (ViewGroup) findViewById(R.id.activity_display_message);

Should be:

RelativeLayoutlayout= (RelativeLayout ) findViewById(R.id.content);

Solution 4:

Here is the updated solution for this.

Intent is a subclass of Main Activity so there's no need to specify explicitly. That means we can call EXTRA_MESSAGE, instead of MainActivity.

EXTRA_MESSAGE

super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_display_message);

    Intentintent= getIntent();
    Stringmessage= intent.getStringExtra(EXTRA_MESSAGE);
    TextViewtextView=newTextView(this);
    textView.setTextSize(40);
    textView.setText(message);

    ViewGrouplayout= (ViewGroup) findViewById(R.id.activity_display_message);
    layout.addView(textView);

Solution 5:

I have solved the same issue by clean project and then Build the gradle, please try once.